Digne played for PSG between 2013 and 2015 before leaving for Roma. Now the left-back returns to the club, most recently from Aston Villa, where he was teammates with Swede Victor Nilsson Lindelöf.
"I am very honoured to return to Paris Saint-Germain after the wonderful experience I had here more than ten years ago. I am impressed by how the club has developed over the years," Digne said in a statement.
The contract runs until 2029.
The 33-year-old started six of France's eight World Cup matches this summer. Digne has previously played for clubs such as Barcelona, Everton and Lille.
